Samah J Almehmadi

Dr. Samah J Almehmadi

Laboratory Medicine, Umm al-Qura University, Makkah al Mukarramah, Saudi Arabia
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 May 2023 in Frontiers in Pharmacology
Verified
Journal Article
Open access
DRDoha Reda
Doha Reda
Gehad E. ElshopakeyGehad E. Elshopakey
Gehad E. Elshopakey
TATalat A. Albukhari
Talat A. Albukhari
SASamah J Almehmadi
Samah J Almehmadi
Bassem RefaatBassem Refaat
Bassem Refaat
FAFatma M. Abdelhamid
Fatma M. Abdelhamid
Introduction: Nonalcoholic fatty liver disease (NAFLD) is a chronic disease characterized by fat deposits in liver cells, which can lead to hepatitis and fibrosis. This study attempted to explore the protective effect of vitamin D3 (VitD) against NAFLD.Methods: Adult male albino rats were randomized into four separate groups: the negative control group was fed a standard rat chow; the positive group received a high-fat diet (20%) and 25% fructose water (NAFLD); the VitD control group was intramuscularly treated with VitD (1,000 IU/kg BW) 3 days per week for 10 weeks; and the NAFLD group was treated with VitD therapy. Biochemical and hepatic histological analyses were performed. Hepatic oxidative stress and inflammatory conditions were also studied. Hepatic expression of sterol regulatory element-binding protein 1-c (SREBP-1-c), peroxisome proliferator-activated receptor alpha (PPAR-α), and insulin receptor substrate-2 was analyzed by quantitative real-time polymerase chain reaction.Results and discussion: The NAFLD rats exhibited elevated terminal body weight, hepatic injury markers, dyslipidemia, glucose intolerance, and insulin resistance. Moreover, the NAFLD rats had increased SREBP-1-c expression and reduced PPAR-α and IRS-2 expressions. Histological analysis showed hepatic steatosis and inflammation in the NAFLD group. In contrast, VitD administration improved the serum biochemical parameters and hepatic redox status in NAFLD rats. Also, VitD treatment ameliorated hepatic inflammation and steatosis in the NAFLD group by decreasing the expression of SREBP-1-c and increasing the expression of PPAR-α. Overall, these results suggest that VitD could have a protective effect against NAFLD and its associated complication.

3 April 2023 in Biomedicines
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Journal Article
Open access
PDF file
LMLubna A. H. Mansour
Lubna A. H. Mansour
Gehad E. ElshopakeyGehad E. Elshopakey
Gehad E. Elshopakey
FAFatma M. Abdelhamid
Fatma M. Abdelhamid
TATALAT Albukhari
TALAT Albukhari
SASamah J Almehmadi
Samah J Almehmadi
EREngy Risha
Engy Risha
Naringenin (NRG) is one of the most important naturally occurring flavonoids, predominantly found in some edible fruits, such as citrus species and tomatoes. It has several biological activities, such as antioxidant, antitumor, antiviral, antibacterial, anti-inflammatory, antiadipogenic, and cardioprotective effects. The heavy metal lead is toxic and triggers oxidative stress, which causes toxicity in many organs, including the liver and brain. This study explored the potential protective role of NRG in hepato- and neurotoxicity caused by lead acetate in rats. Four groups of ten male albino rats were included: group 1 was a control, group 2 was orally treated with lead acetate (LA) at a dose of 500 mg/kg BW, group 3 was treated with naringenin (NRG) at a dose of 50 mg/kg BW, and group 4 was treated with 500 mg/kg LA and 50 mg/kg NRG for 4 weeks. Then, blood was taken, the rats were euthanized, and liver and brain tissues were collected. The findings revealed that LA exposure induced hepatotoxicity with a significant increase in liver function markers (p < 0.05). In addition, albumin and total protein (TP) and the albumin/globulin ratio (A/G ratio) (p < 0.05) were markedly lowered, whereas the serum globulin level (p > 0.05) was unaltered. LA also induced oxidative damage, demonstrated by a significant increase in malonaldehyde (MDA) (p < 0.05), together with a pronounced antioxidant system reduction (SOD, CAT, and GSH) (p < 0.05) in both liver and brain tissues. Inflammation of the liver and brain caused by LA was indicated by increased levels of nuclear factor kappa beta (NF-κβ) and caspase-3, (p < 0.05), and the levels of B-cell lymphocyte-2 (BCL-2) and interleukin-10 (IL-10) (p < 0.05) were decreased. Brain tissue damage induced by LA toxicity was demonstrated by the downregulation of the neurotransmitters norepinephrine (NE), dopamine (DA), serotonin (5-HT), and creatine kinase (CK-BB) (p < 0.05). Additionally, the liver and brain of LA-treated rats displayed notable histopathological damage. In conclusion, NRG has potential hepato- and neuroprotective effects against lead acetate toxicity. However, additional research is needed in order to propose naringenin as a potential protective agent against renal and cardiac toxicity mediated by lead acetate.

1 February 2022 in Arabian Journal of Chemistry
Verified
Journal Article
Open access
SASamah J Almehmadi
Samah J Almehmadi
AAArwa Alharbi
Arwa Alharbi
MAMatokah M. Abualnaja
Matokah M. Abualnaja
KAKholood Alkhamis
Kholood Alkhamis
MAMona Alhasani
Mona Alhasani
NENashwa Elmetwaly
Nashwa Elmetwaly

1 February 2023 in Biomedicines
Verified
Journal Article
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AEAYA MEGAHED EL-REFAI
AYA MEGAHED EL-REFAI
HGHossam Elshahat Gadalla
Hossam Elshahat Gadalla
FAFatma M. Abdelhamid
Fatma M. Abdelhamid
SASamah J Almehmadi
Samah J Almehmadi
AKAnmar Khan
Anmar Khan
EREngy Risha
Engy Risha
Vitamin D3 (VD3) is a sunshine hormone that regulates cellular proliferation, differentiation, apoptosis, and angiogenesis related to liver parenchyma. We used a thioacetamide (TAA)-induced hepatic fibrosis rat model in our study to investigate the beneficial roles of VD3 to overcome extensive liver fibrosis. Randomly, four equal groups (eight rats per group) underwent therapy for eight successive weeks: a control group, a group treated with TAA 100 mg/kg BW IP every other day, a group treated with VD3 1000 IU/kg BW IM every day, and a TAA+VD group treated with both therapies. Treatment with VD3 after TAA-induced hepatic fibrosis was found to alleviate elevated liver function measures by decreasing ALT, AST, and ALP activity; decreasing total bilirubin, direct bilirubin, cholesterol, and triglyceride levels; and increasing glucose and 25[OH]D3. Rats treated with VD3 showed marked decreases in MDA and increased SOD, CAT, and GSH levels. In addition, CD34 and FGF23 gene expressions were reduced after dual therapy. Liver sections from the TAA+VD group showed markedly decreased hepatic lesions, and Masson’s trichrome stain showed a marked decrease in dense bluish-stained fibrous tissue. The immunohistochemical expression of TGF-β and α-SMA showed markedly decreased positive brown cytoplasmic expression in a few hepatocytes, clarifying the antifibrotic effect of VD3 in hepatic fibrosis. In conclusion, VD3 alleviates hepatotoxicity and fibrosis caused by TAA.

1 December 2020 in International Journal of Nature and Life Sciences
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Journal Article
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SASamah J Almehmadi
Samah J Almehmadi
Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) is the most studied reference protein that catalysis the inter-conversion reaction of glyceraldehyde-3-phosphate into 1,3-diphosphoglycerate using NAD+ as coenzyme. GAPDH is also recognized as an important player in DNA repair mechanisms, autophagic and apoptotic cell deaths and posttranslational modifications. Staphylococcus aureus is Gram positive commensal pathogenic bacteria. In the genome of S. aureus, GapA was assumed to be a glycolytic GAPDH and GapB was assumed to be a gluconeogenic GAPDH. The crystal structure of GapA has already been in preceding studies. However, to my knowledge, no structural studies on the gapB homologue is available in the literature. The main aims of this study were to analyze physicochemical properties and generate a homology model structure of GAPDH homologue GapB in S. aureus. This was carried out by Protparam tool, Phyre2 homology modeling server and PSIPRED secondary structure analysis tool. ProtParam predicted that GapB is a stable and liposoluble protein. Homology modeling studies revealed that each subunit of GapB was made up by two domains: the NAD coenzyme binding-domain and the catalytic domain. The NAD binding domain was shown to contain a Rossman fold. On the other hand, the catalytic domain was made up by a mixture of eight strands of beta sheet and seven alfa helices. PSIPRED analysis revealed that the secondary structure of the GapB contains α-helices (29.91%), extended strands (24.63%) and random coil (45.45%).

16 April 2026 in Pharmaceutics
Verified
Journal Article
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SKSherif Adel Kamar
Sherif Adel Kamar
YMYosra Mohamed Magdy
Yosra Mohamed Magdy
TATamer M.M. Abu Aamara
Tamer M.M. Abu Aamara
ASAmina A. Sedky
Amina A. Sedky
TATahani Mohamed Al-Hazani
Tahani Mohamed Al-Hazani
SKSara Khedr
Sara Khedr
Introduction: Oxidative stress and inflammation are major factors linked to obesity and metabolic dysfunction, leading to a significantly higher risk of related diseases. Atorvastatin and liraglutide possess lipid-lowering, antioxidant, and anti-inflammatory effects that could synergistically improve obesity-related perturbations through modulation of the Nrf2/HO-1 signaling pathway. Methodology: We assessed liraglutide’s pharmacological potential in extending atorvastatin’s benefit on obesity, hyperlipidemia, and fatty liver in rats fed a high-fat diet (HFD) for 12 weeks. We specifically evaluated the effects of liraglutide treatment on atorvastatin-induced anti-inflammatory and antioxidant mechanisms, with a particular focus on Nrf2/HO 1 modulation in adipose and hepatic tissue. In silico analyses, including molecular docking and AlphaFold- Multimer modeling, evaluated the binding affinities of atorvastatin and liraglutide to Nrf2 and HO 1. Results: Compared to ND, the HFD-fed rats had a significantly higher final body weight (362.4 ± 12.7 g vs. 245.6 ± 9.8 g in ND, p < 0.05). There was a marked increase in serum total cholesterol (178.6 ± 9.2 mg/dL vs. 98.3 ± 6.4), fasting glucose (340.1 ± 8.2 mg/dL vs. 82.3 ± 3.1), HbA1c (7.8 ± 0.3 vs. 4.5 ± 0.2), and hepatic COX-2 expression (99.9 ± 6.3 vs 19.6 ± 2.4). The oxidative stress markers were also disturbed, as indicated by SOD (42.5 ± 3.1 vs. 95.2 ± 4.6 U/mg protein), GSH (18.3 ± 1.5 vs. 42.7 ± 2.8 nmol/mg), and p62 (0.005 ± 0.001 vs. 0.125 ± 0.01). Atorvastatin lowered cholesterol (121.2 ± 7.5 mg/dL), COX-2 (61.3 ± 3.3), and body weight (301.7 ± 11.5 g) compared to HFD. Meanwhile, liraglutide caused a greater reduction in body weight (268.5 ± 10.3 g), glucose (112.5 ± 6.7 mg/dL), and COX-2 (42.2 ± 2.9) than atorvastatin. The combination therapy produced the most significant effects, returning body weight (253.6 ± 9.1 g) to baseline, normalizing glucose and lipids, reducing COX-2 to 22.9 ± 2.0, and reactivating the Nrf2/HO-1 pathway, as shown by increased HO-1 expression and the restoration of p62 levels (0.078 ± 0.004). In silico analyses suggest that atorvastatin favorably binds to Nrf2 and HO-1, while liraglutide interacts with structurally relevant interfaces on these proteins, providing a mechanistic basis for their complementary antioxidant and cytoprotective effects. Conclusions: Our findings support targeting the Nrf2/HO-1 signaling pathway as a potential therapy for reversing hyperlipidemia and preventing mediators of inflammation and oxidative stress damage in the liver tissue. The evidence of increased efficacy observed with the combined atorvastatin and liraglutide supports a potential novel understanding of the complementary effects of atorvastatin and liraglutide. This finding requires further investigation to elucidate the combination’s therapeutic advantages in treating metabolic disorder scenarios.